#include <stdio.h>
#include <math.h> 

int UlawToLinear(int in)
{
  int S, E, M, V;

  S = (in & 0x80) >> 7;
  E = (in & 0x70) >> 4;
  M = in & 0x0f;
  V = (1 - 2*S) * ( pow(2,E) * (2*M + 33) - 33 );
  return(V);
}

int LinearToUlaw(int x)
{
  int S, i, curr, last, V;

  if (x>=0) S = 0;  /* Keep track of sign and make x positive. */
  else { S = 0x80; x = -x; }
  last = 0; V = 127;
  for (i=1; i<128; i++) {
    curr = UlawToLinear(i); 
    if (curr >= x) {
      if ( (curr-x) < (x-last) ) V = i;
      else V = i - 1;
      break;
    }
    last = curr;
  }
  return(V+S);
}

void main()
{
  int i, j, position;
  int pcmIN, linearOUT, pcmOUT;
  double atten, attenDB, fpcmOUT;

  for (position=0; position<=31; position++) {  /* Make 32 256-byte tables. */
    printf("%i attenuation (dB): ");  /* Get amount in dB from designer,        */
    scanf("%f\n", attenDB);    /*  negative for attenuation, positive for gain. */
    atten = exp(log(10)*attenDB/10); /* Convert to fraction. */
    for (i=0; i<=15; i++) {  /* Construct output file in rows of 16. */
      printf("%04x:", position*256 + i*16);
      for (j=0; j<=15; j++) {
        pcmIN = i*16 + j;
        fpcmOUT = atten * UlawToLinear(pcmIN);
        if (fpcmOUT >=0) linearOUT = floor(fpcmOUT + 0.5);  /* Rounding */
        else linearOUT = ceil(fpcmOUT - 0.5);
        pcmOUT = LinearToUlaw(linearOUT);
        printf(" %2x", pcmOUT);
      }
      printf("\n");
    }
  }
}